Convert yapb (Yet Another PhotoBlog Wordpress Plugin which is not anymore maintained) images to native Wordpress post feature image

convert_yapb_images_to_post_thumbnail.php

<?php

function convert_yapb_images_to_post_thumbnail () {
  require_once ABSPATH . 'wp-admin/includes/image.php';
  global $wpdb;
  $imagefileList = array();
  $imageRows = $wpdb->get_results(
    'SELECT id,post_id,uri FROM ' . YAPB_TABLE_NAME . ' WHERE processed<>1  ORDER BY id'
  );
  //$len=count($imageRows)
  $len = 100;
  for ($i=0; $i<$len; $i++) {
    $row = $imageRows[$i];
    $yapbImage = new YapbImage($row->id, $row->post_id, $row->uri);
    array_push($imagefileList, [$row->post_id, $yapbImage->systemFilePath()]);
  
    $post = get_post($row->post_id);

    $file_path        = $yapbImage->systemFilePath();
    $file_name        = basename($file_path);
    $file_type        = wp_check_filetype($file_name, null);
    $attachment_title = sanitize_file_name(pathinfo($file_name, PATHINFO_FILENAME));
    $wp_upload_dir    = wp_upload_dir();

    $post_info = array(
		  'guid'           => $wp_upload_dir['url'] . '/' . $file_name,
		  'post_mime_type' => $file_type['type'],
		  'post_title'     => $attachment_title,
		  'post_content'   => '',
		  'post_status'    => 'inherit',
	  );

    $attach_id = wp_insert_attachment($post_info, $file_path, $post->ID);

    $attach_data = wp_generate_attachment_metadata($attach_id, $file_path);

    wp_update_attachment_metadata($attach_id, $attach_data);

    set_post_thumbnail($post->ID, $attach_id);

    $q = $wpdb->prepare(
      'UPDATE ' . YAPB_TABLE_NAME . ' SET processed=1 WHERE id=%s',
      $row->id
    );

    $wpdb->query($q);
  }
}